Problem You are given an array nums of positive integers and a positive integer k. A subset of nums is beautiful if it does not contain two integers with an absolute difference equal to k. Return the number of non-empty beautiful subsets of the array nums. A subset of nums is an array that can be obtained by deleting some (possibly none) elements from nums. Two subsets are different if and only if the chosen indices to delete are different. ...
Problem Given a collection of numbers, nums, that might contain duplicates, return all possible unique permutations in any order. Example 1: Input: nums = [1,1,2] Output: [ [1,1,2], [1,2,1], [2,1,1] ] ...
Problem A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequence at most once. Note that the path does not need to pass through the root. The path sum of a path is the sum of the node’s values in the path. Given the root of a binary tree, return the maximum path sum of any non-empty path. ...
Problem Given two strings s and goal, return true if you can swap two letters in s so the result is equal to goal, otherwise, return false. Swapping letters is defined as taking two indices i and j (0-indexed) such that i != j and swapping the characters at s[i] and s[j]. For example, swapping at indices 0 and 2 in "abcd" results in "cbad". Examples Example 1: ...
Problem Given two parameters n and k and returns the value of Binomial Coefficient C(n, k). Definition Binomial coefficients, denoted by C(n, k), have two common interpretations: the coefficient of X^k in the expansion of (1 + X)^n. For eg., in (1 + X)^3, C(3, 2) gives you the coefficient of the term X^2. Expanding the expression, we see 3X^2, and indeed, C(3, 2) is equal to 3. the number of ways to choose k objects from a set of n, regardless of order. Formula $$ C(n, k) \text{ OR } \binom{n}{k} = \frac{n!}{k! * (n - k)!} $$ ...
Problem Given two integer arrays inorder and postorder where inorder is the inorder traversal of a binary tree and postorder is the postorder traversal of the same tree, construct and return the binary tree. Example Example 1: 3 / \ 9 20 / \ 15 7 ...
Problem Given two integer arrays preorder and inorder where preorder is the preorder traversal of a binary tree and inorder is the inorder traversal of the same tree, construct and return the binary tree. Examples Example 1: 3 / \ 9 20 / \ 15 7 ...
Problem Given an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i - j) <= k. Examples Example 1: Input nums = [1,2,3,1], k = 3 Output: true ...
Problem Given an array of integers, find out whether there are two distinct indices i and j in the array such that the difference between nums[i] and nums[j] is at most t and the difference between i and j is at most k. OR You are given an integer array nums and two integers indexDiff and valueDiff. Find a pair of indices (i, j) such that: ...
Problem Given the head of a singly linked list where elements are sorted in ascending order, convert it to a height-balanced binary search tree. A height balanced BST: a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. Examples Example 1: Input: nums = [1, 2, 3, 4, 5, 6] Output: [3,2,5,1,null,4,6] Explanation: [4,2,5,1,3,null,6] is also accepted. ...